Differential cross sections for low-energy electron-impact excitation of the unresolved combinations of 2 3B 2 + 2 1A 1 and 3 1A 1 + 2 1B 2 electronic states of pyrimidine are reported. Comparisons are made with recent differential cross section measurements for the electron-impact excitation of the 1E 1u and unresolved 1B 1u + 3E 2g electronic states of benzene [H. Kato, M. Hoshino, H. Tanaka, P. Limão-Vieira, O. Ingolfsson, L. Campbell, M.J. Brunger, J. Chem. Phys. 134 (2011) 134308.], in order to evaluate the nature of electron impact π-π transitions in aromatic species.